Circuit breaker



Jan. 19, 1937. H. J. LINGAL 2,057,935

' CIRCUIT BREAKER Filed Nov. 2, 1935 4 Sheets-Sheet 1 I INVENTOR MTNESSES. Z75 fivy/Zz/zya/ BY a We, I I ATTORN Jan. 19, 1937. UNGAL 2,067,935

CIRCUIT BREAKER Filed Nov. 2, 1935 4 Sheets-Sheet 2 INVENTOR ATTORNEY Jan. 19, 1937.. H, J L'IN AL 2,067,935

CIRCUIT BREAKER Filed Nov. 2, 1933 4 Sheets-Sheet 3 j; 67 iii.

mm\\\m WITNESSES: I I INVENTOR ayj/dy /f/7/Z/@a/.

M Mai? ATTORN Y J. LI NGAL CIRCUIT BREAKER Jan. 19, 1937.

Filed Nov. 2, 1953 4 Sheets-Sheet 4 INVENTOR WITNESSES Patented Jan. 19, 1937 CIRCUIT BREAKER Harry J. Lingal, Wilkinsburg, Pa., assignor to Westinghouse Electric & Manufacturing Company, East Pittsburgh, Pa., a corporation of Pennsylvania Application November 2, 1933, Serial No. 696,329

23 Claims.

My invention relatesgenerally to circuit interrupters and particularly to multi-pole circuit breakers for use in controlling distribution-and industrial network circuits.

Circuit breakers for this type of service are subjected to very severe and very exacting operating requirements. The available power in the circuits is ordinarily quite large; this results in large magnitude short circuit currents which must be interrupted as quickly as possible. Despite this moderate overloads are of comparative frequent occurrence, and it is very undesirable that the circuit should be opened until such moderate overloads have persisted for a cohsiderable period of time. Furthermore, due to the multi-phase characteristic of certain of these networks, it is imperative that the circuits controlled by the several poles be all opened and closed substantially simultaneously in order to prevent damage to the protected equipment.

Thus, a satisfactory circuit breaker of this type must include means manually or otherwise operable to open and to close a plurality of poles substantially simultaneously; and it must include automatically operable circuit opening means capable of accurately distinguishing between transient overloads and short circuit conditions, the breaker to be opened only after a time-delay following the occurrence of moderate overloads, and to be opened substantially instantaneously on the occurrence of short circuit conditions. Moreover, to prevent damage to the supply circuits, it is necessary that the circuits controlled by all of the poles of the breaker be opened upon the occurrence of a dangerous overload condition in the circuit controlled by any one of the poles; and further, in order to reduce the everyday 1 R loss to a minimum, and to prevent any chattering of the contacts during the occurrence of overloads, it is necessary that the breaker mechanism include means for producing high contact pressure at all times between the cooperating contact surfaces.

It is an object of my invention, therefore, to provide a multi-pole circuit breaker which shall include means operable in response to the move ment of a single operating member for substantially simultaneously opening and closing all of the cooperating contacts, which shall include means for causing the opening of all of the poles of the breaker following the occurrence of predetermined overload conditions in the circuit controlled by any one of those poles, and which shall include means for securing high contact pressure between the coperating contact surfaces of the several poles.

Another object of my invention is to provide an improved multi-pole circuit breaker that shall include a plurality of individual operating mechanisms which are connected in tandem in order to permit the breaker to be operated in response to the movement of a single operating member.

A further object of my invention is to provide a multi-pole circuit breaker utilizing a plurality of individual operating mechanisms with means whereby the several operating mechanisms are actuable in response to the operation of a single trip device to'move all of the contacts to the open circuit position,

A still further object of my invention is to provide an improved multi-pole circuit interrupter according to the above objects of my invention which shall be more reliable in operation, and more economical to manufacture than the previously known devices of this type.

One form of multi-pole circuit breaker which has been used in the past includes a plurality of switch arms mechanically tied together and a single operating mechanism for moving all of the switch arms to the open and to the closed circuit positions. This arrangement is usually satisfactory where the number of poles involved does not exceed three. When the number of poles exceeds three, however, the forces which must be transmitted through the tie means used for connecting the several switch arms to the single operating mechanism become so large that high contact pressure between the engaging contact surfaces can be secured only by the provision of very large and very costly parts. A more satisfactory arrangement is the provision of a plurality of operating mechanisms, suitable means for connecting those mechanisms in tandem so that the several switch arms can be simultaneously moved to the open and to the closed circuit positions upon the actuation of a single operating member, and means operable in response to an overload condition in any one of the poles of the breaker for causing all of the switch members to be moved to the open circuit position. This is the arangement which I prefer to utilize in the preferred embodiment of my invention.

The features ofinvention and the method which I prefer to employ in accomplishing the objects thereof will be made more apparent by reference to the following drawings and description, wherein: V

Figure 1 is a plan view of a four-pole circuit breaker embodying the principal elements of my invention. A portion of the cover of the trip device and a portion of the cover of the breaker itself have been cut away in order to more com-- pletely illustrate the structural features;

Fig. 2 is a sectional view, partly in elevation, on the line 11-11 of Fig. 1;

Figs. 3, 4 and 5 are fragmentary views show ing the operating mechanism and the switch arms of the breaker illustrated in Figs. 1 and 2 in the closed, the open, and the tripped positions, respectively; v

Fig. 6 is a perspective view of the assemblage of switch arms and the two operating mechanisms used in the embodiment of my invention disclosed in Figs. 1 and 2.

Fig. 7 is a fragmentary plan view, partly in section, showing the portion of the trigger associated with each of the two operating mechanisms and the tie-means used for mechanically interconnecting those triggers;

Fig. 8 is a sectional view taken on the line VIII--VIII of Fig. '7.

Fig. 9 is a perspective view of the latch engaging member which forms a part of the tiemeans used for interconnecting the two triggers; and,

Fig. 10 is an enlarged sectional view, partly in elevation, taken on the line'X--X of Fig. 2, showing the main operating handle and the method of connecting the operating members associated with each of the individual mechanisms thereto.

The preferred embodiment of my invention comprises, generally a base I of molded insulating material, a pair of terminals 3 and 5 for each of the four poles of the breaker, a stationary con tact 1 and a switch arm 9 which includes a moving contact H for each of the four poles of the breaker, a tie-bar l3 for mechanically intercomnecting the four switch arms 9, a pair of operating mechanisms l5 which are connected in tandem, and a trip device l1 which includes a thermally-responsive and a magnetically-responsive trip element for each of the four poles of the breaker. The various structural elements of the trip device 11 are mounted upon a separate base l9, likewise of molded insulating material, and the trip device is removable as a unit from the breaker closure. A cover 2| is provided for the breaker closure and a separate cover 23 is provided iorithe trip device l1. Suitable "bailles which-are molded in the base I and which cooperate with similarly shaped battles 21 molded in the cover 2| of the breaker, are provided for preventing flashover between the several poles..

Each of the stationary contacts 1 comprises, generally, a flat strip 29 of conducting material which is provided with a suitable opening (not shown) at one end for engaging one of the termi nal bolts 3| and a raised portion 33 at the other end for supporting the main stationary contact 35 and the stationary arcing contact 31, as is shown particularly in Figs. 2 and 3. The comducting strips 29 are rigidly affixed to the base I by means of suitable screw fastenings 33 (Fig. 2). Each of the moving contacts H comprises a cast body member of conducting material which is pivotally supported on the cooperating switch member frame 4| by means of a suitable pivot pin 43. Contact portions 45 and 41 are provided for cooperating with the main stationary contacts 35 and the arcing contacts 31. Each of the moving contacts I I includes a rearwardly extending portion 49 which is adapted to be engaged by a leaf-spring 5| for biasing the contacts in a counter-clockwise direction about the support pin 43. This spring 5| is adapted to provide the contact pressure between the engaging surfaces of the moving and the stationary contacts when the breaker is in the closed circuit position.

Each of the switch member frames ll coin prises a substantially U-shaped member which is preferably formed of iron or other inexpensive material. Suitable holes are provided in the opposed side portions of each frame for engaging the pivot pin 43 which supports the associated moving contact member H, the pin 43 being prevented from disengaging the frame by a pair of cotter pins 53. The four frames 4| are mechanically tied together by means of a square tie bar 13, preferably of steel, which extends across the several poles of the breaker, the bar 13 being rigidly connected to the rear portion of each of the frames II by means of a metallic strap 54 which is affixed at its ends to the frame itself. Suitable means 55 of insulating material is interposed between the straps 54 and the tie-bar I3 in order to prevent short circuiting of the several poles.

A flexible shunt 51, formed of a plurality of thin copper laminations, is provided for e1ectrically connecting each of the moving contacts II with the trip device I1. One end of the shunt 51 is welded or otherwise conductively joined to-the central portion of the moving contact I l and the other end terminates in a flat contact portion 59 which is adapted to be conductively joined to one of the terminals 58 of the trip device by means of a screw 6!.

The trip device I1 is provided with four looped members 63 of conducting material, each of which is provided with a pair of terminal portions 58 and 64. These members are adapted to be electrically connected in series with each of the poles of the breaker and serve as energizing means for both the thermally responsive and the magnetically responsive trip elements. The terminal portions 58, as discussed above, are adapted to be electrically connected to the terminal portions 59 of the conducting shunts 51, and the terminal portions 54 are adapted to be connected to the terminals 5 of a circuit breaker by means of the terminal bolts 65.

The electrical circuit through each of the poles of the breaker is thus comparatively direct. Beginning with the terminal 3 the current flows successively through the conducting strip 29, the

stationary contact 1, the moving contact H, the flexible shunt 51, thence through the looped conducting member 63 forming a portion of the trip device I1 to the other terminal 5.

Each of the operating mechanisms 15, as is shown particularly in Figs. 2 to 6, includes a substantially U-shaped frame 61 which is used for supporting the other elements of the mechanism, a pair of pivotally connected toggle links 69 and 1|, one end of which engages one of the switch arm frames II, a trigger 13 for releasably engaging the other end of the interconnecting toggle links, a pair of over-center springs 15 for moving the toggle links from one position to the other with a snap action, and an operating member 11 connected to the knee oi. the toggle links by means of the springs 15. The assemblage formed by the interconnected switch arms 9 is pivotally supported on the two U-shaped frames 51 by means of two pins 19, one of which extends through suit-able openings in the sides of the Til frame 4| of each of the two central switch arms to engage the associated mechanism frame 6'I.'

The operating mechanisms I5 are operatively connected to the assemblage of switch arms 9 through the engagement of each of the lower toggle links 69 with one of the two central switch arm frames 4|, a suitable pin 8| being provided for accomplishing this result.

The bifurcated operating members 11, as is shown particularly in Fig. 10, are provided with suitable openings 83 in the ends of each of the two side portions thereof for pivotally engaging the support pins 85 which extend through the sides of the operating mechanism frame 61. The two operating members 11 are mechanically connected together through the agency of a handle member 86 of insulating material, and it is thereby possible to actuate both of the mechanisms by movement of the single handle member 86.

In each of the two mechanisms I5 the upper end of the interconnected toggle links 69 and 'II is pivotally supported on the trigger I3 by means of a pin 81. The trigger itself is pivotally supported on the frame 61 by means of a pin 89 and is biased in the counter-clockwise direction about the pin 89 through the reaction forces of the over-center springs I5. Thus, when the trigger 13 is released by the trip latch 9|, due to the actuation of the trip device II, the operating mechanism moves from the position shown in Fig. 2 so as to cause the interconnected switch arms 9 to move to the open circuit position independently of the position of the operating members 11.

The triggers I3 for the two operating mechanisms I5 are mechanically connected together by means of a square tie-rod 93, preferably of steel. The outer surface of this rod is covered with a tube of insulating material, and the portions of the rod which engage the triggers are carefully insulated therefrom in order to prevent short circuiting of the breaker. A latching member 91 which is adapted to engage the trip latch 9| is affixed to the mid-point of the bar 93 and is insulated therefrom by the tube 95, This arrangement permits both of the triggers I3 to be released upon the occurrence of predetermined conditions in the circuit controlled by any one of the poles of the breaker, and thus assures the substantially simultaneous movement of the two operating mechanisms to the open circuit position.

As shown in Figs. 7 and 8, the square tie-rod 93 terminates at either end in a threaded member 99, the cross sectional area of which is considerably less than that of the cooperating nut IIII. The opening I02 in the end of each of the triggers 13 through which the threaded members 99 extend is of similar outline and as a result the tie-rod is prevented from turning about its axis regardless of the degree of tightness of the retaining nuts IIII. Three insulating washers I03, I04 and I95, which are positioned as shown in Fig. '7, serve to insulate the tie-rod 93 from each of the triggers TI. The latching member 91 comprises a U-shaped member of sheet metal which is provided with a struck out portion III! for engaging the trip latch 9|. The plate I09 is utilized to affix the latch member to the bar 93.

The trip latch 9| is pivotally and slidably sup? ported upon a suitable pin III which, in turn, is supported upon bracket members 3 affixed to the base I9 of the trip device. A spring II5 biases the latch 9| in a counter-clockwise directends across the four poles of the breaker.

tion (Fig. 2) about the pin III. The latch 9|, itself, as is shown particularly in Figs. 1 and 2, comprises a pair of side portions having slots I I6 therein for engaging thepin I I I. These slots are inclined upwardly, as is shown particularly in Fig. 5, in order that the force transmitted to the latch from the operating mechanisms I5 shall aid in holding the latch in the closed position. Movement of the latch 9| in a counterclockwise direction about the pivot pin III is limited by means of an L-shaped projection II! which extends upwardly from the base of the bracket member II3. The provision of the slots H6 in the side portions of the latch member 9| permits that member to slide in the direction of the base I9 of the trip device during the resetting of the circuit breaker mechanism, movement in this direction being opposed by the bowed portion II9 of the spring H5.

The trip device IT, as mentioned above, includes a looped conducting strip 63 which is connected inseries with the circuit controlled by each of the poles of the breaker. Each of these conducting strips 63 is Used to energize a bimetallic thermany-responsive element I20'and a magnetically-responsive element I22. A single, pivotally supported trip bar I2I, of insulating material, ex-

This bar I2| is provided with a projecting portion I23 for retaining the latch 9| in the latched position and is biased to that position by means of a spring I25 which engages a suitable recess in the base I9 of the trip device and in the end of a downwardly projecting portion I2'I formed integral with the trip bar itself. The mechanical advantage of the trip bar and the latch is such that the exertion of a very small force by the trip bar will balance a comparatively large force at the operating mechanism.

Upon the occurrence of a moderate overload condition in the circuit controlled by any one of the poles of the breaker the associated bimetallic thermally responsive element I29 is caused to move in a direction away from the base I9 of the trip device. If the overload persists for a suflicient period of time, the free end of the bimetallic element engages the trip bar I2I and causes that member to rotate so as to release the latch 9|, thereby bringing about the opening of all of the poles of the breaker. Similarly, upon the occurrence of a short circuit or very heavy overload condition in the circuit controlled by any one of the poles of the breaker, the armature I29 (Fig. 2) which forms a part of the magnetically-responsive element I22 associated with that pole is caused to move against the biasing action of its spring I3I so as to rotate the trip bar I2I in a clockwise direction to the tripped position. The latch 9| is disengaged by the trip bar exactly the same as for the thermal operation, and all of the poles of the breaker open automatically. A screw I33 is provided for calibrating and adjusting each of the thermally-responsive elements I22.

While my invention is not particularly concerned with the structural details of the trip device I I, it has been necessary to point out some of manually the operating handle 86 is moved in a counter-clockwise direction about its pivot point, the pins 85. This movement of the operating handle 86 is transmitted to each of the two bifurcated operating members 11 and by moving them causes the line of action of the over-center springs 15 for each of the two mechanisms to be brought to the right (Fig. 3) of the pivot pin 81 which connects the upper toggle links 1| to the trigger 13. As soon as this position has been reached, the knee pivot pin I35 oi. the toggle links is biased in the direction of the base I9 of the trip device I1 by a force which progressively increases as the handle is moved. When this biasing force reaches a suflicient magnitude to overcome the force holding the knee of the toggle links in the over-center position shown in Fig. 3, the knee pivot pin I35 of both of the operating mechanisms will move from the position shown in Fig. 3 to the position shown in Fig. 4, and the interconnected switch arms 9 will, substantially si multaneously, move from the closed circuit to the open circuit position. The opening movement once initiated takes place with a snap action, due to the fact that any movement of the knee pivot pins I35 results in a progressive increase in the iorce producing such movement. In this connec tion, it is important to note that the switch arms 9 are individually biased to the open circuit position due to the stressing of the contact pressure securing spring during the closing of the breaker, and also that when the breaker is in the closed circuit position it is effectively locked therein, due to the fact that the knee pivot pins I35 for the two sets of toggle links have moved to an over-center position. Thus, when the breaker is in the fully closed position the engaging contact surfaces of the cooperating contacts are held against each other with a substantially fixed force, and, due to the fact that the assemblage of switch arms is engaged by two mechanisms at two different points,;very little mechanical distortion of the tie means which might lessen the contact pressure can take place. High contact pressure is thus assured under all possible operating conditions.

To close the contacts manually, the operating handle 36, and with it the two mechanically in terconnected operating members 11, are moved from the position shown in Fig. 4 toward the position shown in Fig. 3. The result of this movement is to bring the line of action of the overcenter springs 15 for each of the two mechanisms across the point where the upper toggle link 1| is pivoted to the trigger 13,-whereupon a component of force is produced which tends to move the inter-connected switch arms to the closed circuit position. When the combined components for each of the two operating mechanisms reaches a sufficient magnitude, the four interconnected switch arms 9 are caused to move to the closed circuit position with a snap action, due to the fact that any movement of the knee pivot pin results in a progressive increase in the component of force tending to produce that movement, exactly as discussed above with regard to the circuit opening operation.

When the circuit breaker and the two operating mechanisms are in the position.shown in Fig. 3, each of the triggers 13 is biased in a counter-clockwise direction about its individual pivot pin 39 by the reaction force of the overcenter springs 15, which is transmitted through the toggle link N. This force is balanced by the trip latch 9|, the trip latch being thereby biased in a clockwise direction about its pivot pin III. Upon the occurrence of an overload condition capable of causing the trip bar I to release the latch 9 I, that member is free to 1'0- tate so as to disengage the portion I01 of the latching member 91 which is mechanically connected to the two triggers 13. The triggers are then free to move in a counter-clockwise direc tion under the biasing action of the two sets of over-center springs 15, the limit of motion in this direction being defined by the engagement of the heel portion I31 of each of the triggers 13 with the portion I39 that connects the sides of each of the U-shaped frames 61. However, before the limit of motion of the interconnected triggers 13 has been reached, the pivot pins 81 which connect the upper toggle links II to the triggers 13 have been moved to the left of the line of action of the over-center springs 15. In this position, the toggle linkages are no longer able to hold the inter-connected switch members 9 in the closed circuit position, and those members begin to move toward the open circuit position under the combined biasing action of the contact pressure-securing springs 5I and the over-center springs 15.

Any movement of the interconnected members in this direction results in a progressive increase in the force exerted by the over-center springs 15 tending to produce this movement and the result is a substantially instantaneous collapse of the toggle which results in a similar instantaneous opening of all of the poles of the breaker. When the breaker is in the tripped position the various elements of each of the two operating mechanisms I5 and the interconnected switch arms 9 are in the position shown in Fig.5. The latch 9|, following the opening of the circuit breaker, immediately returns to the normal latched position under the biasing action of the spring II5.

Following each opening of the interrupter as a result of the actuation of the trip device I1, it is necessary to restore the two operating mechanisms I5 to an operative position. This is done by rotating the single operating handle 86 from the mid-position (Fig. 5), which is the position assumed by that member when the breaker opens as a result of the actuation of the trip device, to the open circuit position which is shown in Fig. 4. This movement of the operating handle B6 is transmitted to the individual operating mechanisms through the engagement of the downwardly projecting portions III of each of the bifurcated operating members 11 with the rear portion I31 of each of the triggers 13. The triggers 13 are thereby caused to rotate in a clockwise direction until the latching portion I01 of the member 91, which is rigidly supported on the means for interconnecting the triggers, engages the over-hanging portion I43 of the latch 9|. Further movement causes the latch to slide along the pin III so as to permit the over-hanging portion I 43 to reengage the latching portion I01 of the connecting means. re-engagement takes place with a snap action, shortly before the handle 86 is moved to the full oif position (Fig. 4). The breaker is then completely reset and the switch arms 9 may be manually moved to the closed circuit position exactly as described above. The various elements of the trip device are automatically resettable and need not be considered for the purposes of this invention.

Reduced to its simplest elements, my inven- This tion comprises a plurality of switch arms which are mechanically interconnected and which are movable to the open and to the closed circuit positions through the actuation oi? single operating handle, the operating handle being in turn mechanically connected to a pair of operating mechanisms, each of which is mechanically connected to the assemblage formed by the interconnected switch arms, and each of which includes a member biased to cause the associated operating mechanism to move the contacts to the open circuit position. In addition, my invention comprises means for interconnecting these two biased members in such manner that both of them may be released at the same time upon the actuation of the trip device. Thus, my invention provides for securing the simultaneous opening and closing of a plurality of poles upon the occurrence of an overload in any one of those poles or upon the actuation of a suitable operating lever.

As mentioned above, the bifurcated operating members 71 are mechanically connected to the interconnected triggers 13 only through the overcenter springs Hi. This, in connection with the fact that the pivot pins 87 which connect the upper toggle links H to the triggers 13 are moved a sufilcient distance, following the release of the interconnected triggers by the trip device, to break the toggle with respect to the line of action of the over-center springs i5, even if the handle 86 is held in the closed circuit position, causes the breaker to be entirely trip free of the operating handle under all possible operating conditions.

From the foregoing it will be seen that I have disclosed an improved multi-pole circuit interrupter wherein the moving contacts for the several poles of the breaker are moved substantially simultaneously to the open and to the closed circuit positions with a snap action/and which include means for assuring adequate contact pressure between the engaging surfaces of the cooperating contact members'without the necessity of providing mechanical parts of inordinate size or excessive cost. In addition to the above, I have shown how a plurality of operating mechanisms may be utilized for actuating the plurality of switch arms of a multi-pole circuit breaker in response to the movement of a single operating member. Moreover, I have disclosed how a plurality of operating mechanisms can be so connected in tandem that all of the interconnected operating mechanisms will move, upon the occurrence of an over-load in the circuit controlled by any one of the poles of the breaker, to cause the opening of all of the poles of the breaker.

While in accordance with the patent statutes I have disclosed the features of a preferred embodiment of my invention, it is to be understood that many of these features are merely illustrative and that variations in their precise form will be possible without departing from the essence of my invention. I desire, therefore, that my invention shall be limited only by what is expressly stated in the claims and by the prior art.

I claim as my invention:

1. In a multi-pole circuit interrupter; contact means movable to open and to close a plurality of poles; a plurality of individual operating mechanisms, each of which is adapted to actuate the contact means for at least one of said poles, and each of which includes a trigger member, means biasing said trigger members to move and cause the associated contact means to be moved automatically from one position to the other; means for mechanically interconnecting said trigger members; a single latch for engaging and re straining all of said interconnected trigger members from movement by said biasing means, said latch being releasable to cause the contact means associated with said interconnected trigger members to be moved from one position to the other; and electro-responsive means for actuating said latch upon the occurrence of predetermined conditions.

2. In a multi-pole circuit interrupter; contact means movable to open and to close a. plurality of poles; a plurality of individual operating mechanisms each of which is adapted to actuate the contact means for at least one of said poles, each of said operating mechanisms including an operating member movable to cause the associated contact means to be moved from one position to the other, and a trigger member movable to cause said operating mechanism to automatically move the associated contact means from the closed circuit position to the open circuit position; means for mechanically interconnecting said operating members, said interconnected operating members having a handle portion by which they are directly movable in unison; means for mechanically interconnecting said trigger members; latch means for engaging and normally holding said interconnected trigger members in fixed position, said latch means being releasable only to cause the contact means associated with said interconnected members to be automatically moved from the closed circuit position to the open circuit position upon the occurrence of a. predetermined electrical condition; and electroresponsive means for actuating said latch means upon the occurrence of said predetermined condition.

3. In a multi-pole circuit interrupter; contact means movable to open and to close a plurality of poles; a plurality of individual operating mechanisms, each of which is adapted to actuate the contact means for at least one of said poles, each of said operating mechanisms including an operating member, a spring through which the force exerted on the operating member is transmitted to cause the associated contact means to be moved from one position to the other, and a trigger member movable, independently of the position of said operating member, to cause said operating mechanism to move the associated contact means from the closed circuit position to the open circuit position; means for mechanically interconnecting said operating members; means for mechanically interconnecting said trigger members; latch means for engaging said interconnected trigger members, said latch means be ing releasable to cause the contact means associated with said interconnected members to be automatically moved from the closed circuit position to the open circuit position; and electroresponsive means for actuating said latch upon the occurrence of predetermined conditions.

4. In a multi-pole circuit interrupter; contact means movable to open and to close a plurality of poles; a plurality of individual operating mechanisms, each of which is adapted to actuate the contact means for at least one of said poles, each of said operating mechanisms including a trigger member movable to cause said operating mechanism to automatically move the associated contact means from the closed circuit position to the open circuit position; means for mechanically interconnecting said trigger members;

means ior biasing said trigger members to cause said contact means to be moved from the closed circuit position to the open circuit position; releasable latch means for engaging said interconnected trigger members to restrain said members against movement under the biasing action of said biasing means; and electro-responsive means for causing said latch means to release said assemblage upon the occurrence of predetermined conditions.

5. In a multi-pole circuit interrupter; contact means movable to open and to close a plurality of poles; mechanisms, each of which is adapted to actuate the contact means for at least one of said poles, each of said operating mechanisms including a trigger member movable to cause the associated contact means to be moved automatically from one position to the other by said operating mechanism, and means'ior biasing said trigger member to cause said contact means to be moved from one position to the other; means formechanically interconnecting said trigger mem-.

; the contact means for at least one of said poles,

each of said operating mechanisms including an operating member movable to cause the assoelated contact means to be moved from one position to the other, and a trigger member movable to cause said operating mechanism to automatically move the associated contact means from the closed circuit position to the open circuit position; means for mechanically interconnecting said operating members; means for mechanically interconnecting said trigger members; means for biasing said interconnected trigger members to cause said contact means to be moved from the closed circuit position to the open circuit position; releasable latch means for engaging the assemblage formed by said trigger members and the connecting means therefor to restrain said interconnected movable members against movement under the biasing action of said biasing means; and electro-responsive means for causing said latch means to release said assemblage upon the occurrence of predetermined conditions.

7. In a multi-pole circuit interrupter; contact means movable to open and to close a plurality of poles; a plurality of individual operating mechanisms, each of which is adapted to actuate the contact means for at least one of said poles, each of said operating mechanisms including an operating member movable to both open and close the circuit, spring means actuable in response to movement of said operating member to cause the associated contact means to be moved from one position to the other with a snap action in both opening and closing the circuit, a

trigger member movable to cause said operating mechanism to move the associated contact means from one position to the other, with a snapv action, and means biasing said trigger member to cause said contact means to be moved from a plurality of individual operating one position to the other; means for mechanically interconnecting said operating members; means for mechanically interconnecting said trigger members; releasable latch means for engaging the assemblage formed by said trigger members and the connecting means therefor to restrain said trigger members against movement under the biasing action of said biasing means; and electro-responsive means for causing said latch means to release said assemblage upon the occurrence of predetermined conditions.

8. In a multi-pole circuit interrupter; contact means movable to open and to close a plurality of poles; a plurality of individual operating mechanisms, each of which is adapted to actuate the contact means ior at least one of said poles, each of said operating mechanisms including an operating member movable to cause the associated contact means to be moved from one position to the other, and a trigger member movable, independently of the position of said operating member, to cause said operating mechanism to move the associated contact means from the closed circuit position to the open circuit. position; means for mechanically interconnecting said operating members; means for mechanically interconnecting said trigger members; spring means for biasing said trigger members to cause said contact means to be moved from the closed circuit position to the open circuit position; releasable latch means for engaging said connecting means to restrain said trigger members against movement under the biasing action of said biasing means; and electro-responsive means for causing said latch means to release said connecting means upon the occurrence of predetermined conditions.

9. In a multi-pole circuit interrupter; contact means movable to open and to close a plurality of poles; a plurality of individual operating mechanisms, each of which is adapted to actuate the contact means for at least one of said poles, each of said operating mechanisms including an operating member, spring means actuable in response to movement of said operating member to cause the associated contact means to be moved from one position to the other with a snap action, a trigger member movable, independently oi the position of said operating memher, to cause said operating mechanism to move the associated contact means from one position to the other, and means biasing said trigger member to cause said contact means to be moved from one position to the other; means for mechanically interconnecting said operating members; means for mechanically interconnecting said trigger members; releasable latch means for engaging the assemblage formed by said trigger members and the connecting means therefor to restrain said trigger members against movement under the biasing action of said biasing means; and electro-responsive means for causing said latch means to release said assemblage upon the occurrence of predetermined conditions.

10. In a multi-pole circuit interrupter; contact means movable to open and to close a plurality of poles; a plurality of individual operating mechanisms, each of which is adapted to actuate the contact means for at least one of said poles, and each of which includes a trigger member movable only upon the occurrence of an abnormal condi tion to cause the associated contact means to be moved automatically from one position to the other, each of said trigger members being at the potential of one pole; means comprising a bar,

at least partially of insulating material, which extends across at least two of the poles of said interrupter for causing said operating mechanisms to normally open and close all of said poles together, and means of insulating material for mechanically interconnecting and at the same time electrically insulating said trigger members; latch means for engaging said interconnected members; said latch means being releasable to cause the contact means associated with said interconnected members to be moved from one position to the other; and electro-responsive means for actuating said latch means upon the occurrence of said abnormal condition.

11. In a multi-pole circuit interrupter; contact means movable to open and to close a plurality of poles; a plurality of individual operating mech anisms, each of which is adapted to actuate the contact means for at least one of said poles, each of said operating mechanisms including an operating member, spring means actuable in response to movement of said operating member to cause the associated contact means to be moved to both open and closed positions with a snap action, and a trigger member movable to cause said operating mechanism to automatically move the associated contact means from the closed circuit position to the open circuit position; means for mechanically interconnecting said operating members; means comprising a bar which extends across at least two of the poles of said interrupter, and which is at least partially of insulating material for mechanically interconnecting and at the same time electrically insulating said trigger members; a single latch for engaging said interconnected trigger members, said latch being releasable to cause the contact means associated with said interconnected members to be automatically moved from the closed circuit position to the open circuit position; and electro-responsive means for actuating said latch upon the occurrence of predetermined conditions.

12. In a multi-pole circuit interrupter; contact means movable to open and to close a plurality of poles; a plurality of individual operating mechanisms, each of which is adapted to actuate the contact means for at least one of said poles, each of said operating mechanisms including an operating member, spring means actuable in response to movement of said operating member to cause the associated contact means to be moved from open position to closed position with a snap action, and a trigger member movable, independently of the position of said operating member, to cause said operating mechanism to move the associated contact means from the closed circuit position to the open circuit position; means comprising a bar, at least partially of insulating material which extends across two or more poles of said interrupter for mechanically interconnecting said trigger members; a latch means including a pivoted member for engaging said interconnected members, said latch means being movable to release said interconnected members to cause the contact means associated with said interconnected members to be automatically moved from the closed circuit position to the open circuit position; and electro-responsive means for actuating said latch upon the occurrence of predetermined conditions.

13. In a multi-pole circuit interrupter; contact means movable to open and to close a plurality of poles; a plurality of individual operating mechanisms,- each of which is adapted to actuate the contact means for at least one of saidpoles, each of said operating mechanisms including a trigger member movable to cause said operating mechanism to automatically move the associated contact means from the closed circuit position to the open circuit position; means comprising a bar, at least partially of insulating material, which extends across at least two of the poles of said interrupter for mechanically interconnecting said trigger members; means for biasing said trigger members to cause said contact means to be moved from the closed circuit position to the open circuit position; releasable latch means for engaging said connecting means to restrain said trigger members against movement under the biasing action of said biasing means; a plurality of electro-responsive means, each of which is electrically connected in the circuit controlled by one of the poles of said interrupter; and means operable by any one of said electro-responsive means to cause said latch means to release said connecting means.

14. In a multi-pole circuit interrupter; contact means movable to open and to close a plurality of poles; a plurality of individual operating mechanisms, each of which is adapted to actuate the contact means for at least one of said poles, each of said operating mechanisms including a trigger member movable only upon the occurrence of an abnormal condition to cause said operating mechanism to move the associated contact means from one position to the other, and means for biasing said trigger member to move and cause said contact means to be moved from one position to the other; means comprising a bar, at least partially of insulating material, which extends across at least two of w the poles of said interrupter for mechanically interconnecting said trigger members; means for biasing said contact means to be moved from the closed circuit position to the open circuit position upon movement of said interconnected trigger members; releasable latch means for engaging said connecting means to restrain said interconnected members against movement under the biasing action of their biasing means; a plurality of electro-responsive means, each of which is electrically connected in the circuit controlled by one of the poles of said interrupter; and means operable by any one of said electro-responsive means upon the occurrence of said abnormal condition to cause said latch means to release said connecting means.

15. In a multi-pole circuit interrupter; contact means movable to open and to close a plurality of poles; a plurality of individual operating mechanisms, each of which is adapted to actuate the contact means for at least one of said poles, each of said operating mechanisms including an operating member, spring means actuable in response to movement of said operating member to cause the associated contact means to be moved from open position to closed position with a snap action, and a trigger member movable to cause said operating mechanism to automatically move the associated contact means from the closed circuit position to the open circuit position; means comprising a bar, at least par tially of insulating material which extends across two or more poles of said interrupter for mechanically interconnecting said trigger members; a latch means including a single pivoted member for engaging said interconnected members, said latch means being movable to release said interconnected members to cause the contact means associated with said interconnected members to be automatically moved from the closed circuit position to the open circuit position; and 75 electro-responsive means for actuating said latch upon the occurrence of predetermined conditions.

16. In a multi-pole circuit interrupter; contact means movable to open and to close a pluralityof poles; a plurality of individual operating mechanisms each of which is adapted to actuate the contact means for at least one of said poles, each of said operating mechanism including an operating member, spring means ,actuable in response to movement of said operating member to cause the associated contact means to be moved from open position to closed position with a snap action, a trigger member movable to cause said operating mechanism to move the associated contact means from one position to the other, and means biasing said trigger member to cause said contact means to be moved from one position to the other; means comprising a bar, at least partially of insulating material which extends across two or more poles of said interrupter ior mechanically interconnecting said trigger members; a latch means including a single pivoted latch member for engaging said interconnected members, said latch means being movable to release said interconnected members to cause the contact means associated with said interconnected members to be automatically moved from the closed circuit position to the open circuit position, and electroresponsive means for actuating said latch upon the occurrence of predetermined conditions.

17. In a multi-pole circuit interrupter; contact means movable to open and to close a plurality of poles; a plurality of individual operating mechanisms, each of which is adapted to actuate the contact means for at least one oi? said poles, each of said operating mechanisms including an operating member at least one of which forms a handle movable to cause the associated contact means tobe moved from one position to the other, and a trigger member movble to cause said operating mechanism to move the associated contact means from the closed circuit position to the open circuit position; means comprising a bar, at least partially of insulating material, which extends across at least two poles of said interrupter for mechanically interconnecting said operating members to move at all times in unison with the operating member forming the handle; means comprising a second bar, likewise at least partially of insulating material, which also extends across at least two poles of said interrupter for mechanically interconnecting said trigger members; latch means for engaging and normally holding said interconnected trigger members in fixed position, said latch means being releasable on y to cause the contact means associated with said interconnected members to be atuomatically moved from the closed circuit position to the open circuit position; and electro-responsive means for actuating said latch upon the occurrence of predetermined conditions.

. 18. In a multi-pole circuit interrupter; contact means movable to open and to close a plurality of poles; a plurality of individual operating mechanisms, each of which is adatped to actuate the contact means for at least one of said poles, each of said operating mechanisms including an operating member movable to cause the associated contact means to be moved from one position to the other, and a trigger member biased to move, independently of the position of said operating member, and cause said operating mechanism to move the associated contact means from the closed circuit position to the open circuit position; means comprising a bar, at least partially of insulating material, which extends across at least two poles of said interiupter for mechanically interconnecting said operating members; means comprising a second bar, likewise at least partially of insulating material, which also extends across at least two poles of said interrupter for mechanically interconnecting said trigger members; releasable latch means for engaging and holding the assemblage formed by said trigger members and the connecting means therefor against their bias, said latch means being releasable only upon the occurrence of an abnormal condition to cause the contact means associated with said interconnected trigger members to be automatically moved from the closed circuit position to the open circuit position, independently of the position of said interconnected operating members; and electro-responsive means for causing said latch means to release said assemblage upon the occurrence of said abnormal condition.

19. In a multi-pole circuit interrupter; contact means movable to open and to close a plurality of poles; a plurality oi individual operating mechanisms, each of which is adapted to actuate the contact means for at least one of said poles, each of said operating mechanisms including an operating member, spring means actuable in response to movement of said operating member to cause the associated contact means to be normally moved to both open and closed positions with a snap action, a trigger member movable to cause said operating mechanism to automatically move the associated contact means from the closed circuit position to the open circuit position, and means biasing said trigger member to cause said operating mecha nism to move the associated contact means from the closed-circuit position to the open-circuit position; means comprising a bar, at least partially of insulating material, which extends across at least two poles of said interrupter for mechanically interconnecting said operating members; means comprising a second bar, likewise at least partially of insulating material, which also extends across at least two poles of said interrupter for mechanically interconnecting said trigger members; releasable latch means for engaging the assemblage formed by said trigger members and the connecting means therefor to restrain said members against movement under the biasing action of said biasing means; and electroresponsive means for causing said latch means to release said assemblage upon the occurrence of predetermined conditions.

20. In a multi-pole circuit interrupter; contact means movable to open and to close a plurality of poles; a plurality of individual operating mechanisms, each of which is adapted to actuate the contact means for at least one of said poles, each of said operating mechanisms including a separate frame member, a movable operating member supported thereon, spring means actuable upon the movement of said operating member to cause the associated contact means to be normally moved to both open and closed positions with a snap action, and a trigger mem-' ber movable independently of the position of said operating member, to cause said operating mechanismto move the associated contact means from the closed circuit position to the open circuit position, said trigger member being normally at the potential of the associated pole;

means comprising a bar, at least partially of insulating material, which extends across at least two poles of said interrupter for mechanically interconnecting said operating members; means comprising a second bar, which also extends across at least two poles of said interrupter and includes means of insulating material for mechanically interconnecting and at the same time electrically insulating said trigger members, means for biasing said trigger members to cause said contact means to be moved from the closed circuit position to the open circuit position; latch means for engaging said interconnected members, said latch means being releasable to cause the contact means associated with said interconnected members to be automatically moved from the closed circuit position to the open circult position; and electro-responsive means for actuating said latch means upon the occurrence of predetermined conditions.

21. In a four-pole circuit interrupter; four stationary contacts; four switch arms for cooperating therewith to open and to close the electrical circuit through the four poles of said interrupter; means for mechanically interconnecting said switch arms for simultaneous movement; means for actuating said interconnected switch arms consisting of two separate actuating mechanisms, one of which is operatively connected to each of the two centrally disposed switch arms; each of said actuating mechanisms including an operating member movable to effeet the normal operation thereof and a trigger member movable from a normal inoperative position to an operative position to effect automatic operation of said mechanism; means for mechanically interconnecting both of said operating members and both of said trigger members in order to accomplish simultaneous operation of said mechanisms; a single pivoted latch member which normally restrains said interconnected trigger members in said inoperative position; and trip means operable upon the occurrence of predetermined conditions to cause said latch mem-' her to release said interconnected trigger members and permit those members to move to said operative position; said trip means including a plurality of electro-responsive elements, each energized in response to the electrical circuit controlled by one of the poles of said interrupter, and a single trip bar which normally holds said latch in a position where it restrains said interconnected trigger members in said inoperative position; said trip bar extending across a plurality of the poles of said interrupter and being movable to effect the release of said latch by any one of said electro-responsive elements.

22. In a four-pole circuit interrupter; four stationary contacts, four switch arms arranged side-by-side for cooperating therewith to open and to close the electrical circuit through each of the four poles of said interrupter; means for actuating said switch arms consisting of a separate actuating mechanism operatively connected to each of the two centrally disposed switch I arms; a bar member mechanically connected to the two centrally disposed switch arms and having an outwardly extending portion at either end thereof for engaging and supporting the two outer switch arms; said bar member serving to mechanically interconnect all four of said switch arms in order to permit the operation of said interrupter by said two actuating mechanisms; each of said actuating mechanisms including an operating member movable to effect the normal operation thereof, a trigger member movable from a normal inoperative position to an operative position to effect automatic operation of said mechanism from the closed circuit position to the open circuit position, and means normally biasing said trigger member to said operative position; means for mechanically interconnecting said operating members and said trigger members in order to accomplish simultaneous operation of both of said mechanisms; a single pivoted latch member which normally restrains said interconnected trigger members in said inoperative position against the force 01' said biasing means; and trip means operable upon the occurrence of predetermined conditions to cause said latch member to release said interconnected trigger members and permit those members to be moved to said operative position by said biasing means; said trip means including a plurality of electro-responsive elements, each energized in response to the electrical circuit controlled by one of the poles of said interrupter, and a single trip bar which normally holds said latch in a position where it restrains said interconnected trigger members in said inoperative position; said trip bar extending across a plurality of the poles of said interrupter and being movable to effect the release of said latch by any one of said electro-responsive elements.

23. In a four-pole circuit interrupter; four stationary contacts, four switch arms for cooperating therewith to open and to close the electrical circuit through the tour poles of said interrupter; means including a bar member which extends across all of the poles of said interrupter for mechanically interconnecting said switch arms for simultaneous movement; means for actuating said interconnected switch arms consisting of two separate actuating mechanisms, one of which is operatively connected to each of the two centrally disposed switch arms; each of said actuating mechanisms including an operat ing member movable to effect the normal operation thereof, a trigger member movable from a normal inoperative position to an operative position to effect automatic operation of said mechanism from the closed circuit position to the open circuit position, irrespective of the position of said operating member, and means which normally biases said trigger member to said operative position; means for mechanically interconnecting said operating members and said trigger members in order to accomplish simultaneous operation of said mechanisms; a single pivotally supported latch member which normally restrains said interconnected trigger members in said inoperative position against the force of said biasing means; and trip means operable upon the occurrence of predetermined conditions to cause said latch member to release said interconnected trigger members and to permit those members to be moved to said operative position by said biasing means; said trip means including four thermally responsive bimetallic elements, each of which is heated in response to the current flowing in the circuit controlled by one of the poles of said interrupter, and a single pivot-' ally supported trip bar movable from a normal inoperative position, in which position it holds said latch in a position Where it restrains said interconnected trigger members from being moved to said operative position by said biasing means, to an operative position, in which position it permits said latch to disengage said interconnected trigger members.

HARRY J. LINGAL. 

